A large and cold air mass from the Canadian Rockies descended over the US northern Rockies and stalled over the region. Enough moisture was drawn into the system from the Pacific to direct decent snowfall over portions of central and eastern Montana.
Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GGW wrote it up.
A large and cold air mass from the Canadian Rockies descended over the US northern Rockies and stalled over the region. Enough moisture was drawn into the system from the Pacific to direct decent snowfall over portions of central and eastern Montana.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Glasgow, MT wrote its last area forecast discussion before the first event at Apr 1, 2:46 AM MST, 14 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 346 AM MDT Wed Apr 1 2020 .DISCUSSION... Snow, steady at times, will continue to affect portions of NE Montana through this afternoon before diminishing this evening and tonight. The steadier snowfall amounts are set to occur over the Little Rockies and extending south to Petroleum and Garfield Counties and then tracking NE toward the Glendive, Sidney, and Plentywood areas. This is where 3 to 6 inches will likely fall and combine with gusty winds to create blowing and drifting conditions. Northern Valley County, meanwhile, may see little accumulation given the dry environment setting up north of the midlevel low track. All things considered, have left winter weather headlines untouched for now. A few places in the NE zones may approach warning criteria, but messaging and impacts are similar whether a low end advisory and a high end warning. Colder than normal temperatures will prevail across NE Montana through the balance of the week before rebounding nicely over the upcoming weekend. Latest 500mb heights suggest an upper level ridge building over the region at that time with dry and mild weather conditions expected. Maliawco && .AVIATION... A range of MVFR to LIFR conditions are expected with low ceilings and reduced visibilities associated with snow passing through the region today. KSDY to KGDV will see the more persistent steadier snowfall today. Snow will end this afternoon and evening with a gradual return to VFR expected tonight. Maliawco && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 3 PM MDT this afternoon for Garfield...Petroleum. Winter Storm Warning until noon MDT today for Southwest Phillips. Winter Weather Advisory until 6 PM MDT this evening for Dawson... Eastern Roosevelt...McCone...Prairie...Richland...Sheridan... Western Roosevelt. Winter Weather Advisory until noon MDT today for Central and Southeast Phillips...Central and Southern Valley. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
4 winter storm. Local standard time, as filed.
Trained spotter in Flatwillow reported 6 inches of new snow. Times are estimated.
Snowfall reports from central and northern portions of Garfield County ranged from 6 to 8 inches. The greatest amount of 8 inches was reported from 17N Van Norman. Times are estimated.
Trained spotter about 30W Vida reported 7 inches of new snow. Times are estimated.
Trained spotter 9.5 NW Carlyle reported 7 inches of new snow. Times are estimated.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2020Every state in 2020This day in weather historyWarnings in Montana, April 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 881810, 880566, 880574, 880560.